Mono-2-haloethyl esters of 2-haloethanephosphonic acid

ABSTRACT

WHEREIN BOTH X&#39;&#39;s represent the same halogen, i.e. either bromine or chlorine, preferably chlorine. The compounds are plant growth regulators comparable 2-chloroethanephosphonic acid.   Mono-2-haloethyl esters of 2-haloethanephosphonic acid represented by the formula:

United States Patent [72] Inventors David I. Randall;

Robert W. Wynn, both of Easton, Pa. [21] Appl. No. 710,652 [22] FiledMar. 5, 1968 [45] Patented Dec. 7, 1971 [73] Assignee GAF CorporationNew York, N.Y.

[54] MONO-2-HALOETHYL ESTERS 0F 2- HALOETHANEPHOSPHONIC ACID 2 Claims,No Drawings [52] 0.5. Cl 260/961, 71/86, 260/983, 260/986 [51] Int. ClA0ln 9/36, C07f 9/40 [50] Field of Search 260/961 [56] References CitedUNITED STATES PATENTS 2,708,204 5/1955 Bell et al 260/961 X 3,296,1321/1967 Petersenetal.

Primary Examiner-Joseph P. Brust Assistant Examiner-Richard L. RaymondAllorneys-George L. Tone, Homer .1. Bridger, Martin A.

Levitin, Samson B Leavitt and Walter C. Kohm of Z-haIoethane' ABSTRACT:Mono-Z-haloethyl esters phosphonic acid represented by the formula:

O/OH xom-cm-l I oom-oinx MONO-Z-HALOETHYL ESTERS F 2-HALOETHANEPHOSPHONIC ACID This invention relates to new and usefulmono-2-haloethyl esters of 2-chloroethanephosphonic acid, and moreparticularly to the mono-2-chloroethyl ester of 2-chloroethanephosphonic acid, sometimes also called 2- or beta-,chloroethylphosphonic acid.

Such mono-2-haloethyl esters of chloroethanephosphonic acid, eitheralone or in admixture with the 2 chloroethanephosphonic acid per se, orvarious other esters of such acid, have been found to be plant growthregulators comparable in activity to 2-chloroethanephosphonic acid perse.

The novel mono-2-haloethyl esters of 2- chloroethanephosphonic acid maybe prepared in good yield and purity from the correspondingbis-(2-haloethyl ester) of 2-chloroethanephosphonic acid in severalways. Thus, the bis- (2-ha1oethyl ester) of 2-chloroethanephosphonicacid may first be converted to monohaloethyl ester of 2-chloroethanephosphonyl chloride by reaction with PCL,,, as illustratedin Equation 1 below:

OCH CHgX clomon i ClCH CH X PO01;

OCHQCHQX and the thus obtained phosphonyl chloride hydrolyzed tochloroethanephosphonic acid may be partially cleaved by reaction withHCl to produce the desired mono-2-haloethyl ester ofZ-chloroethanephosphonic acid, as illustrated in equation III:

III

ll c1cH,oH,-P clomomx OCHQCHjX In the foregoing equations 1, I1 and Ill,X represents bromine or chlorine.

The details of the preparation of the novel compounds of the presentinvention will be apparent from a consideration of the followingspecific examples which are illustrative of preferred embodimentsthereof.

EXAMPLE 1 1n the manner illustrated in equations l and i] above, themono-2-chloroethyl ester of 2-chloroethanephosphonic acid was preparedin the following manner:

A 250 cc., 4-necked flask equipped with stirrer, thermometer, nitrogeninlet, and 96inch X12 inches vigreaux column to distillation head wascharged with 53.9 g. (0.2 moles) of the bis- (2-chloroethyl ester) ofchloroethanephosphonic acid. Maintaining the temperature below C., withstirring, there was added portionwise in 10 minutes 43.7 g. (0.22 mole)of phosphorus pentachloride under a nitrogen blanket. After the additionwas completed the mixture was refluxed at a pot temperature of 1 12l l3C. for 2 hours. The volatile material was then removed by distillationunder a nitrogen stream to a pot temperature of 156 C. The residue, 51.4g., was distilled at reduced pressure After a forerun of 3.6 g., removedat 1l8-l25 C. at 2.0 mm., 34.6 g. (77 percent theory) of themono-Z-chloroethyl ester of 2- chloroethanephosphonyl chloride wasobtained boiling at l26l 29 C. at 2.2 mm. Hg.

The thus obtained phosphonyl chloride was then hydrolyzed to the freeacid in the following manner:

10.5 g. of the thus obtained phosphonyl chloride was stirred with cc. ofdistilled water while warming on steam bath. ln 10 minutes dissolutionwas complete. 9.0 g. of the mono-2- chloroethyl ester of2-chloroethanephosphonic acid was obtained in pure form, by removing thewater via a rotary flask evaporator, as a clear colorless viscous oil.The titration curve was typical for a monofunctional strong acid. Theneutral equivalent gave the correct molecular weight for the formula:

Nuclear Magnetic Resonance analysis confirmed the structure, as didelemental analysis.

EXAMPLE 2 1n the manner illustrated in equation 111 above, the mono-2-chloroethyl ester of 2-chloroethanephosphonic acid was prepared by thefollowing procedure:

100 parts of crude bis-(2-chloroethyl ester) of chloroethanephosphonicacid are charged into a 4-neck flask equipped with stirrer inlet tube,condenser and thermometer. At C. anhydrous HCl gas is passed through forabout 15 hours at a good rate. Excess HCl gas is adsorbed in a scrubbingtower and the 1,2-dichloroethane evolved is collected. There was thusobtained 70 g. of a viscous, clear liquid, which analyzed about 40percent 2-chloroethanephosphonic acid and 40 percent ofmonoQ-chloroethyl ester of 2-chloroethane phosphonic acid. This mixture,of the betachloroethanephosphonic acid and the mono-2- chloroethylesters thereof, exhibited plant growth regulator activity similar tothat exhibited by the two components of the mixture. The puremono-2-chloroethyl ester of 2- chloroethanephosphonic acid was recoveredfrom the mixture by extraction with benzene. The ester being readilysoluble in benzene, was removed in solution in the benzene from the 2-chloroethanephosphonic acid which was essentially insoluble in thebenzene. After removal of the benzene by evaporation under vacuum, thethus recovered mono-Z-chloroethyl ester of 2-chloroethanephosphonic acidwas found to be identical with the product obtained in example 1.

While the foregoing examples illustrate the preparation of the preferredmono-Z-chloroethyl ester of 2- chloroethanephosphonic acid, it will beunderstood that the 2- bromoethyl ester may be prepared in an analogousmanner and yield, by starting with the bis-( 2-bromoethyl ester) of 2-bromoethanephosphonic acid.

As stated above, the mono-2-haloethyl esters of 2-chloroethanephosphonic acid, particularly the mono-2- chloroethyl esterthereof, are especially valuable for use as a plant growth regulator byapplication to plants, either alone or in admixture with the2-chloroethanephosphonic acid, in essentially any proportions, i.e. inrelative proportions of the monoester to acid of from 1:99 to 99: 1.,although as a practical matter, it is preferred to employ such mixturesin the ratio of 1:9 to 9:1 by weight.

The effect of the mono-2-chloroethyl ester of 2- chloroethanephosphonicacid on living plants and its manner of use thereon is essentially thesame as that of the 2- chloroethanephosphonic acid per se. This efiectand use is more fully described in copending application Ser. No.617,860 filed Feb. 23, 1967 and now abandoned by Charles D. Fritz andWilbur F. Evans, entitled Growth Regulator Process Utilizing PhosphonicCompounds," and the application of Anson R. Cooke, Ser. No. 659,310,filed Aug. 9, 1967, and now abandoned entitled Method of InitiatingFlowering," and the disclosure of said copending applications aretherefore incorporated in the present application by reference.

We claim:

wherein X represents bromine or chlorine.

2. The

chloroethanephosphonic acid.

monoQ-chloroethyl ester

2. The mono-2-chloroethyl ester of 2-chloroethanephosphonic acid. 